Automated ribosomal intergenic spacer analysis
It is a high throughput technique involving PCR amplification
of ribosomal intergenic regions (16S–23S for
archaea and bacteria; 18S–28S for fungi) using a fluorescence
labeled primer (Fisher and Triplett 1999). The
electrophoresis is performed on an automated system
with laser detection of fluorescence DNA fragments
resulting in a complex community-specific banding pattern,
where each band corresponding to at least one
organism in the original community. The differences in
the sizes of amplified intergenic region form the basis
of subtyping of bacterial strains (Larue et al. 2005;
Welkie et al. 2010). Welkie et al. (2010) showed that
bacterial community composition in liquid and solid
phases of same diet fed to dairy cows differed substantially.
Using automated ribosomal intergenic spacer analysis
(ARISA), Pulmonari et al. (2010) revealed that
Megasphaera elsdenii is associated with milk fat depression
in dairy cows where mean pH of rumen content is
6.3–6.33. ARISA was used to elucidate rumen fungi
diversity in cow (Denman et al. 2008; Cheng et al.
2009a, b). In another study, Edwards et al. (2008) used
ARISA for studying the colonization dynamics of anaerobic
fungi on perennial ryegrass.